1. Technical Field
The use of a cordless electrical connector in domestic appliances such as kettles, coffee/tea makers and irons for supplying power e.g. to the heating element thereof, and the benefits this brings, are well known. Cordless connectors which allow for engagement of the appliance with the power base regardless of their relative angular orientation, often known as 360° connectors, are popular due to the ease of use which they provide. An example of a basic 3-pole electrical connector is disclosed in the Applicant's prior application published as WO 95/08204. Such a connector is available from Strix Limited under the product name P72.
2. Background Information
In its basic form the appliance part of the cordless connector has, on its underside, a central line pin and two concentric annular conductors. The smaller diameter conductor is for the neutral component of the mains supply, whilst the outermost one is an earth connection. The corresponding base part of the connector has a central aperture for the line pin surrounded by an annular slot for receiving the neutral ring. Electrical connection is made via sprung contacts inside the base connector part below the aperture and a portion of the annular slot respectively, which are biased against the line pin and neutral ring respectively. The base connector part fits within the outermost earth ring of the appliance connector part and has an outwardly sprung contact on one side for making connection to the inner face of the earth ring.
The Applicant has also devised a 5-pole cordless electrical connector which provides two further electrical connections in addition to the basic power connection to the appliance. Such a 5-pole connector is described in the Applicant's prior application published as WO 01/28294. An example is available from Strix Limited under the product name P76. The P76 connector is designed to interface with a Strix U67 control unit, wherein a temperature sensor is connected via the two additional conductor rings in the connector to provide temperature information to control circuitry provided in the power base, for example to a Strix EK03 base electronic control system. An advantage of 5-pole connectors such as the Strix P76 connection system is that the control unit may be provided in the power base while a main electrical component such as a heating element and a further functional component such as a temperature sensor may be provided remotely in the appliance, with the cordless connector enabling both power transmission to the main component and data/control signals to be transmitted to and from the functional component via the additional connections. This has the advantage that electrical power to the control unit in the base may be maintained regardless of whether the appliance is on the base or not. Also the functional component may be placed in an optimum position in the appliance for its intended purpose. In the case of a sensor, for example, it may be positioned in close proximity to the main component so as to be capable of accurately sensing operation of the main component.
It has been recognized by the Applicant that it may be desirable to provide more than one functional component in the appliance in addition to the main power-drawing component. Electronic beverage making appliances, for example, may provide various functions in addition to heating liquid. Further functional components in the appliance may include a temperature sensor, illuminating means, liquid pump, motor for moving parts such as an infusion basket for tea or a grinder for coffee, etc. However each functional component will require one if not two electrical connections in addition to the three standard power connections (line, neutral, earth) to the main component.
Although one theoretical solution is to increase the number of terminals in the cordless connection system, for example moving from a 5-pole connector to a 7-pole connector, this is undesirable for a number of reasons, e.g. the connector would become larger and heavier, and as the number of conductors increased it would become more difficult to engage the two connector parts, in particular over a range of angles as is desirably provided by a 360° connector. Furthermore it would significantly increase the cost of the connector system to include further terminals.
Furthermore the Applicant has appreciated that in any electrical appliance comprising a cordless connector it may be desirable for two components in the appliance to be able to share a common pair of electrical connections provided by the connector.